This invention relates to filler neck caps, and particularly to a rotatable cam-on cap for closing the open mouth of a filler neck. More particularly, this invention relates to a cam-on filler neck cap having means for retaining the cap in an installed filler neck-closing position on the filler neck.
Conventional fuel caps for closing the filler neck of a vehicle fuel tank typically include a closure member for closing the mouth of the filler neck and a handle for turning the closure member to mount the closure member in the filler neck. Partial turn cam-on caps and multiple turn threaded caps are well-known types of caps for use in closing filler necks. Although such caps are currently in widespread use, it would be desirable to provide an alternative cap that is simpler to install on and remove from a filler neck.
It is known to provide a cam-on cap of the type having a shank portion which extends into the filler neck and is provided with pairs of conventional circumferentially spaced-apart cam lugs as disclosed in U.S. Pat. No. 4,887,733 to Harris. These cam lugs operate in the customary way to engage a filler neck configured to receive a cam-on cap and retain the cap in a fully tightened position closing the open mouth of the filler neck.
Alternatively, a conventional multiple turn cap includes a closure member that is threaded to be screwed into a threaded filler neck. For example, U.S. Pat. No. 3,820,680 to Friend discloses a multiple turn threaded cap and a compatible threaded filler neck. Typically, a multiple-turn threaded cap must be turned at least two and one-half or three full revolutions by the user after it is inserted into the threaded filler neck to connect the cap to the filler neck and establish a liquid and vapor seal between the cap and the filler neck.
More and more vehicle drivers are using the self-service bays at gasoline stations and filling their own fuel tanks. Some people have found that it is difficult to remove and install a conventional filler neck cap during refueling. A cap that is readily installable on and removable from a filler neck by a user without a lot of effort and that is configured to establish a sturdy sealed connection between the cap and the filler neck consistently during use would be a welcomed improvement over conventional caps.
What is needed is a cap that can be installed easily on a filler neck and that is retained mechanically in its installed filler neck-closing position to maintain fuel system integrity. In its installed filler neck-closing position, a tight seal should be established between the cap and the filler neck to block discharge of liquid fuel and fuel vapor from the filler neck. A cap that is configured to mount on a filler neck so that it is mechanically retained in a sealed filler neck-closing position without applying a load to the mechanical retention means would represent an improvement over conventional filler neck caps.
According to the present invention, a closure assembly is provided for a filler neck having a mouth. The closure assembly includes an inner mounting flange formed to include a notch and means for coupling the inner mounting flange to the filler neck at its mouth. The closure assembly further includes closure means for closing the mouth of the filler neck and handle means for rotating the closure means about an axis of rotation in the filler neck.
The closure means includes a body, an inner retaining member appended to the body, and a detent. The detent is appended to the inner retaining member and is sized to fit into the notch formed in the inner mounting flange during installation of the closure means in the filler neck. The handle means is operable to rotate the closure means relative to the filler neck about the axis of rotation to engage the inner retaining member appended to the body and the inner mounting flange appended to the filler neck and also project the detent into the notch formed in the inner mounting flange. The detent fits in the notch to retain the closure means mechanically in an installed filler neck-closing position closing the mouth of the filler neck.
In preferred embodiments, the detent includes a resilient latch arm having a fixed end cantilevered to the inner retaining member of the body and an opposite free end. An anti-drift lug is appended to the free end of the latch arm for releasably engaging the notch formed in the inner mounting flange appended to the filler neck upon rotation of the closure means in a cap-installation direction to its installed filler neck-closing position. This mechanical retention means provides a snap-fit connection that functions to block rotation of the closure means about its axis of rotation in the filler neck in a cap-removal direction once the operator turns the closure means to its filler neck-closing position using the handle means.
Advantageously, the anti-drift lug is sized to fit into the notch without deflecting the cantilevered latch arm in a downward direction into the filler neck and away from the inner mounting flange on the body upon arrival of the closure means at its installed filler neck-closing position. This extends the useful life of the detent because the latch arm is not loaded once the anti-drift lug snaps into the notch and the latch arm does not take a "thermal set" which might otherwise reduce the spring force of the cantilevered latch arm over time.
Illustratively, the body has a cylindrical shape and includes a pair of circumferentially spaced-apart annular inner retaining members and there is a detent appended to each of the annular inner retaining members. Likewise, a pair of circumferentially spaced-apart annular inner mounting flanges are appended to the filler neck and each inner mounting flange is formed to include a notch for receiving one of the two detents. Thus, there is a detent on each side of the cap for engaging a notch formed on each side of the filler neck to retain the cap mechanically to the filler neck upon arrival of the cap at its installed filler neck-closing position.
In preferred embodiments, the cylindrical body also includes a second pair of circumferentially spaced-apart annular retaining members and the filler neck includes a second pair of circumferentially spaced-apart annular mounting flanges. In the installed position, each second or axially outer retaining member engages one of the second or axially outer mounting flanges to hold the cap in place in the filler neck. At the same time, each axially inner retaining member engages one of the axially inner mounting flanges to assist in holding the cap in place in the filler neck. A detent is appended to each of the axially inner retaining members appended to the cylindrical body and is configured to snap into one of the notches formed in the axially inner mounting flanges appended to the filler neck to retain the body of the closure means in its installed filler neck-closing position.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.